If you know me you'll know I'm not a fan of fitness “shortcuts" (not to be mistaken with "efficiency" of course). These supposed "shortcuts" can often be better translated as "Steaming Piles of B.S. Hidden Behind Genetically Blessed Hot People Who Think Being Hot is Easy."
🤦♀️ Hot people...
However there is one little caveat to the “burn more calories in less time” notion, and that's--
(Which is not as scary as it sounds, I promise).
Every day your body alternates between “fasted” and “fed” states.
Every time you eat a meal, your body enters a “fed” state that lasts about 3-6+ hours as it processes and absorbs the nutrients from the food you just ate, spiking your insulin levels. Once all the nutrients are delivered, insulin levels drop and bring your body into your “fasted” state, which lasts until your next meal.
When you work out after a meal, there’s a surplus of burnable energy from the food you just ate, however, when you work out fasted, it goes straight for the fat cells for it’s fuel (this goes for both dietary fat and bodily fat).
Thus, if you use your fasted downtime effectively by exercising while your stomach is empty, you burn more fat more rapidly, since your body is now able to target its stored fat for fuel (i.e. the stuff clinging to your love handles for dear life), since it's not burning energy from a meal you just ate.
This works for both cardio and strength training. What's more, it even targets your most stubborn, hard-to-get-rid-of fat due to these little chemicals called catecholamines. Yay catecholamines!
And here's the kicker: you can still have your morning cup of coffee or tea before the workout, since anything under 50 calories won't effect your fasted state.
(As a side note, I’m actually a big advocate of moderate caffeine consumption. I’ve done much research on the topic, and I believe the benefits far outweigh any negative effects when consumed in moderation.)
Fasted training obviously works best in the morning (and with "intermittent fasting"), since your stomach's reliably empty, so, whenever possible, I'd suggest this morning routine:
Have your coffee/tea
Do your workout
Have a protein shake or protein-rich breakfast (to enhance "protein synthesis")
Perform this routine 2-5 times/week and you're lookin' at the closest thing to any "fitness shortcut" out there.